Many lifetime growth trajectories for a single mammal

Area of Science:

• Ecology and Evolutionary Biology
• Animal Growth and Development
• Wildlife Population Dynamics

Background:

• Individual growth trajectories are crucial for life history tactics and population dynamics but are rarely studied in wild populations due to data limitations.
• Wild boar (Sus scrofa) exhibit altricial characteristics, polygyny, and significant sexual dimorphism, making them an interesting model for growth studies.

Purpose of the Study:

• To analyze individual wild boar growth trajectories in populations experiencing contrasting environments (rich vs. poor).
• To test evolutionary predictions regarding sex-specific growth patterns and environmental influences on sexual size dimorphism.

Main Methods:

• Utilized long-term longitudinal data from two wild boar populations.
• Applied standard growth models (Gompertz, logistic, monomolecular) to quantify population and individual growth trajectories.
• Analyzed variations in asymptotic body mass, growth rate, and timing of maximum growth rate.

Main Results:

• Wild boar exhibited a Gompertz-type growth trajectory at the population level in the richer environment, with evidence of variation between populations and individuals.
• Significant differences were observed in asymptotic body mass, growth rate, and timing of maximum growth rate, indicating high growth flexibility.
• A cohort effect on asymptotic body mass suggests early-life environmental conditions influence adult size.

Conclusions:

• Wild boar growth trajectories are highly diverse, influenced by environmental context, sex, and year of birth.
• The species demonstrates considerable phenotypic plasticity in growth, challenging simple predictions based on their altricial-precocial classification.